1. Field of the Invention
The present invention relates to a machining tool with a numerical control device, and particularly relates to a machining tool with a numerical control device having adjustment function of gravity center of a main body of the machining tool.
2. Description of the Related Art
A relatively small and lightweight machining tool is often moved a short distance. Moving method includes, hoisting the machining tool with a crane or the like, and lifting the machining tool by a dolly or a lift such as a forklift or a manual forklift. Since a lift itself is compact, the lift is used for relatively short distance relocation, such as relocation in a factory building.
When a lift raises a machining tool, fork position and fork width need to be determined such that a gravity center of the machining tool is located between the two forks of the lift. It is important to grasp the gravity center position of the machining tool to determine the fork position and the fork width.
Japanese Patent Laid-Open No. 2005-131715 discloses a technique in which a transport auxiliary device for an industrial robot uses a forklift. In the industrial robot, engaging holes are formed and exclusive parts are attached to a base portion, such that a gravity center of the whole robot comes between the two forks of the forklift. The forklift inserts the forks to a receiving portion to lift the robot in a stable conveying attitude.
A small machining tool may also be relocated by a lift. For many small machining tools, lift insertion points are not fixed. When a moving part position and a weight of a load mounted on the moving part such as a top face of a table change in every replacement, the gravity center position also changes, so the lift insertion points need to be decided according to the gravity center position.
There are two methods of relocation of a small machining tool by a lift. One method is to raise the machining tool after the lift is positioned according to the gravity center position of the machining tool. The other method is to position the moving part such that the gravity center position comes between the forks after the position of the lift is determined preliminarily.
In the latter method of positioning the moving part after the position of the lift is determined preliminarily, a position of the moving part for stable lifting is determined in the end, after such operations are repeatedly tried that, moving part position where a gravity center position comes between the forks is predicted and assumed first, then the machining tool is lifted, and a moving part position is corrected according to the balance of the lifted machining tool. When the first assumed gravity center position is markedly different from the true gravity center position, trial times increases causing man-hours increase. In addition, there is a possibility that repetition of lifting up and lifting down causes a load on machine parts. Therefore, it is desirable to grasp precisely from the first, a movable part position where the gravity center comes between the forks, so as to reduce number of trials.
In addition to that, lifting operation by a forklift is performed while an electrical source of a machine is deactivated in many cases. In these cases, such a way is adopted that, a movable part position is moved directly by hand forcibly to correct a movable part position, since positioning by a numerical control device is impossible. This way can not be adopted for a machine with a configuration in that the brake is applied to a moving shaft while an electrical power is deactivated.
Considering these things above mentioned, such a machine is desirable that, a moving part is precisely positioned while an electrical power of the machine is activated, for correction of the position of the moving part.